INTRODUCTION: Persistent physical symptoms that are medically unexplained can result in significant functional impairment. The aim of this study was to estimate the prevalence of persistent physical symptoms among people seeking primary healthcare in Reykjavík, Iceland, how they relate to functional impairment, symptoms of depression, general anxiety and health anxiety, and estimate the proportion of people with such symptoms who would likely benefit from psychological treatment. MATERIALS AND METHODS: Questionnaires measuring persistent physical symptoms, functional impairment, and symptoms of depression, general anxiety and health anxiety were administered to 106 patients attending two primary healthcare clinics. RESULTS: The prevalence of persistent physical symptoms was 27.4% among the primary care patients and they had a strong relationship to symptoms of mental disorders. Participants with persistent physical symptoms were 8 times more likely to have clinical levels of depression and general anxiety than participants without such symptoms, 4 times more likely to have clinical levels of health anxiety and 13 times more likely to have clinical levels of functional impairment. At least two-thirds of participants with persistent physical symptoms would likely benefit from psychological treatment. CONCLUSION: The prevalence of persistent physical symptoms among health care patients in the capital area of Iceland is in line with previous studies. Similarly, the strong relationship between persistent physical symptoms and symptoms of depression and anxiety corresponds to previous studies. It is likely that at least two out of three patients with persistent physical symptoms would benefit from psychological treatment. Transdiagnostic cognitive behavioural therapy for persistent physical symptoms might be particularly useful as is focuses on the interplay between physical and mental symptoms.